Summary: Analysis of Factors Affecting Strain Distribution
in Geosynthetics
M. Emin Kutay1
; Murat Guler2
; and Ahmet H. Aydilek3
Abstract: Localized strains due to production defects, seams, and punctured zones significantly affect mechanical performance of
geosynthetic materials. Accurate determination of localized strains becomes particularly important for quality control/quality assurance
evaluation of these materials and may play a critical role in design problems. A battery of tensile tests was conducted on 12 different
geosynthetics to assess the effects of seam type, puncture, and clamping techniques on strain distributions. Digital images of the
geosynthetic specimens were captured during testing, and the analyses of time-lapsed images were performed using two optical flow
techniques to define strain distributions within specimens as well as in the vicinity of grip locations and seam zones. The results indicated
that the optical flow techniques used in this study can successfully define the distribution of strains in a geosynthetic test specimen during
tensile testing. The magnitude of lateral strains was small in polypropylene wovens and geogrids, whereas it was significant in polyester
wovens and nonwovens. Large strains developed in the vicinity of seams regardless of the clamping technique used. The strains at the
seam zones measured with hydraulic grips were significantly higher than those measured with roller grips. Sewn geosynthetics generally
experienced lower lateral strain-to-axial strain ratios. The average axial strain appears to be insensitive to puncture regardless of the type
of geosynthetics considered or the clamping technique used.
DOI: 10.1061/ ASCE 1090-0241 2006 132:1 1
CE Database subject headings: Strain distribution; Imaging techniques; Geosynthetics; Geomaterials.
Introduction